Oil and gas pipeline deformation detection technology
1 caliper detection technology
GM technology is mainly used to detect pipeline geometric distortion caused by external forces to determine the specific location of the deformation, and some use of mechanical devices, some use magnetic induction principle, can detect the pit, ellipse, geometry changes and other effects diameter pipeline the effective inner diameter of the geometric anomalies.
2 Leak Detection Technology
Currently the technology is more mature and acoustic radiation pressure method. The former consists of a pressure measuring-instrument unit, the pipeline needs to be detected in an appropriate injection of liquid. Leak at the lowest pressure area formed in the pipe and leak detection equipment set here; latter acoustic leak detection is based on the use of the unique voice within the range of 20 ~ 40 kHz generated when the pipeline leak through with appropriate frequency selection The electronic device of its acquisition, and to determine the location of the leak is detected at the wheel and the marking system through mileage.
3 by detecting magnetic flux leakage technology (MFL)
In all the pipeline inspection technology, magnetic flux leakage detection longest history, because the tube can be detected on the island, the volume type defects generated by external corrosion on the detection of low environmental requirements can be used for both oil pipelines and gas pipelines, may indirectly determine coating conditions, its most extensive range of applications. Since the leakage flux is a relatively noise process, even without amplification to take any form of data, the abnormal data are recognized in the appropriate channel is also evident, its application is relatively simple. It is worth noting that the use of magnetic flux leakage detector detects the pipeline, the need to control the running speed of the pig, the leakage flux is very sensitive to its operating speed of a vehicle, although the sensor coil sensors currently used alternatives to reduce the speed of the sensitivity, but can not completely eliminate the effects of speed. The technology to uncover when the pipeline requires completely magnetically saturated pipe wall. Therefore, the applicable test accuracy and wall thickness, the greater the thickness, the lower the accuracy, its scope is usually wall thickness not exceeding 12mm. This technique is appropriate to the accuracy of the ultrasonic wave is high, the exact height of the defect to determine the need to depend on the operator’s experience.
4 piezoelectric ultrasonic detection technology
Piezoelectric ultrasonic detection technology principle is used in ultrasonic testing in the traditional sense, the sensor contact with the wall through a liquid coupling, which measure the pipe defects. Ultrasonic detection of cracks and other defects in the most sensitive place type, high detection accuracy is observed that the best method for detecting cracks. However, due to the sensor crystal fragile, easily damaged sensor element in running the pipeline environment, and the keep a continuous crystal sensor coupled through the liquid and the wall, high cleanliness requirements for coupling agent. Therefore, only the liquid pipes.
5 electromagnetic sensing technique (EMAT)
Ultrasound can be excited in a conductive elastic medium in contact with the liquid without the need for mechanical coupling. This technique is the subject of electromagnetic principles of physics to modern sensor technology replaces conventional ultrasonic testing of piezoelectric sensors. When the electromagnetic sensor can upload the wall when the ultrasound excitation, wave propagation has been taken off the inner and outer surface as a “waveguide” manner, when the wall is uniform, wave propagation will be extended wall attenuation; When an exception occurs on the wall, the reflected waves generated in the acoustic impedance at the boundary of the abnormal mutations, refraction and diffuse reflection, the received waveform significant change occurs. Since sound waves bounce the walls of the sensor based on electromagnetic detection of the most important characteristics of a liquid couplant not, is obliged to ensure that its performance. Therefore, this technique provides a feasible gas pipeline ultrasonic testing is an effective alternative method for detecting leakage flux.
Post time: Dec-15-2020